No antithrombotic therapy versus single antiplatelet therapy after percutaneous left atrial appendage closure in non-valvular atrial fibrillation: rationale and design of the multicentre, randomised, non-inferiority NAPT-LAAC trial.

The current standard regimen for antithrombotic therapy after percutaneous left atrial appendage closure (LAAC) in patients with non-valvular atrial fibrillation (NVAF) recommends long-term use of antiplatelet agents. However, this recommendation is not supported by sufficient clinical evidence. Since LAAC is a treatment option for managing patients at high risk of bleeding, it is necessary to clarify whether long-term antiplatelet therapy is truly required after LAAC. The Non-Antithrombotic Versus. Single antiPlatelet Therapy Following Left Atrial Appendage Closure (NAPT-LAAC) trial, a prospective, randomised, controlled, open-label, blinded-endpoint multicentre study, will be conducted in Japan. It was designed to evaluate whether non-antithrombotic therapy is non-inferior to antiplatelet monotherapy after 45 days of oral anticoagulant (OAC) monotherapy following LAAC, with respect to the incidence of thrombotic and bleeding composite events in patients with NVAF and high bleeding risk. Patients with NVAF with a CHA2DS2-VA score ≥2 and who successfully undergo LAAC are eligible for inclusion. A total of 500 patients undergoing LAAC will be randomised (1:1) to aspirin monotherapy versus non-antithrombotic therapy for the 45 days following OAC monotherapy. The primary outcome is a composite of all-cause mortality, myocardial infarction, stroke, systemic embolism, major bleeding, and clinically relevant non-fatal bleeding during a maximum of 4 years of follow-up. Major bleeding or clinically relevant non-fatal bleeding is defined as Type 2, 3, or 5 bleeding, according to the Bleeding Academic Research Consortium definition. The NAPT-LAAC trial will determine the probable non-inferiority of long-term non-antithrombotic therapy to aspirin monotherapy in patients with NVAF who undergo LAAC. (ClinicalTrials.gov: NCT07125417; jRCTs031250110).